Comparison of first attempt success rate of ultrasound-guided internal jugular vein cannulation in supine vs prone position: a prospective randomized controlled trial- PROSPECTUS trial (prone vs supine positioning evaluation for central line insertio

Background: Cannulation of the internal jugular vein (IJV) is traditionally performed in the supine position; however, during surgeries in the prone position, it may become necessary to obtain central venous access because of unexpected blood loss. Methods: This prospective, randomized, open-label, non-inferiority trial was conducted at an academic medical center between May 2024 and June 2025. A total of 192 adult patients requiring IJV cannulation were enrolled and randomly assigned to two groups: the supine (S) group and the prone (P) group. All procedures were performed using an ultrasound (USG)-guided short-axis, out-of-plane approach. The primary outcome was to compare first-attempt success between the supine and prone positions. Secondary outcomes included comparisons of access time, guidewire insertion time, catheterization time, number of attempts, and associated complications. Results: The first-attempt success rate was 90.62% in the supine position compared with 77.08% in the prone position (absolute risk difference, 13.54%; two-sided 90% CI, 4.95–22.13%), indicating that the non-inferiority of prone vs supine was not demonstrated. The prone group had considerably longer access, guidewire insertion, and catheterization times than the supine group ( P < 0.0001). However, despite these statistically significant differences, successful cannulation was achieved in both groups. The complication rates were similar across the two groups ( P = 0.688). Conclusion: In this study, USG-guided IJV cannulation in the prone position did not meet the pre-specified criterion for non-inferiority compared with the supine approach. It was nonetheless achievable in all patients in the hands of skilled practitioners, suggesting its use as a rescue option rather than as a comparable alternative.